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-rw-r--r--image/sanitize.c475
1 files changed, 475 insertions, 0 deletions
diff --git a/image/sanitize.c b/image/sanitize.c
new file mode 100644
index 00000000..e00c8b35
--- /dev/null
+++ b/image/sanitize.c
@@ -0,0 +1,475 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include "kerncompat.h"
+#include "internal.h"
+#include "messages.h"
+#include "utils.h"
+#include "kernel-lib/crc32c.h"
+#include "image/sanitize.h"
+#include "extent_io.h"
+
+/*
+ * Reverse CRC-32C table
+ */
+static const u32 crc32c_rev_table[256] = {
+ 0x00000000L,0x05EC76F1L,0x0BD8EDE2L,0x0E349B13L,
+ 0x17B1DBC4L,0x125DAD35L,0x1C693626L,0x198540D7L,
+ 0x2F63B788L,0x2A8FC179L,0x24BB5A6AL,0x21572C9BL,
+ 0x38D26C4CL,0x3D3E1ABDL,0x330A81AEL,0x36E6F75FL,
+ 0x5EC76F10L,0x5B2B19E1L,0x551F82F2L,0x50F3F403L,
+ 0x4976B4D4L,0x4C9AC225L,0x42AE5936L,0x47422FC7L,
+ 0x71A4D898L,0x7448AE69L,0x7A7C357AL,0x7F90438BL,
+ 0x6615035CL,0x63F975ADL,0x6DCDEEBEL,0x6821984FL,
+ 0xBD8EDE20L,0xB862A8D1L,0xB65633C2L,0xB3BA4533L,
+ 0xAA3F05E4L,0xAFD37315L,0xA1E7E806L,0xA40B9EF7L,
+ 0x92ED69A8L,0x97011F59L,0x9935844AL,0x9CD9F2BBL,
+ 0x855CB26CL,0x80B0C49DL,0x8E845F8EL,0x8B68297FL,
+ 0xE349B130L,0xE6A5C7C1L,0xE8915CD2L,0xED7D2A23L,
+ 0xF4F86AF4L,0xF1141C05L,0xFF208716L,0xFACCF1E7L,
+ 0xCC2A06B8L,0xC9C67049L,0xC7F2EB5AL,0xC21E9DABL,
+ 0xDB9BDD7CL,0xDE77AB8DL,0xD043309EL,0xD5AF466FL,
+ 0x7EF1CAB1L,0x7B1DBC40L,0x75292753L,0x70C551A2L,
+ 0x69401175L,0x6CAC6784L,0x6298FC97L,0x67748A66L,
+ 0x51927D39L,0x547E0BC8L,0x5A4A90DBL,0x5FA6E62AL,
+ 0x4623A6FDL,0x43CFD00CL,0x4DFB4B1FL,0x48173DEEL,
+ 0x2036A5A1L,0x25DAD350L,0x2BEE4843L,0x2E023EB2L,
+ 0x37877E65L,0x326B0894L,0x3C5F9387L,0x39B3E576L,
+ 0x0F551229L,0x0AB964D8L,0x048DFFCBL,0x0161893AL,
+ 0x18E4C9EDL,0x1D08BF1CL,0x133C240FL,0x16D052FEL,
+ 0xC37F1491L,0xC6936260L,0xC8A7F973L,0xCD4B8F82L,
+ 0xD4CECF55L,0xD122B9A4L,0xDF1622B7L,0xDAFA5446L,
+ 0xEC1CA319L,0xE9F0D5E8L,0xE7C44EFBL,0xE228380AL,
+ 0xFBAD78DDL,0xFE410E2CL,0xF075953FL,0xF599E3CEL,
+ 0x9DB87B81L,0x98540D70L,0x96609663L,0x938CE092L,
+ 0x8A09A045L,0x8FE5D6B4L,0x81D14DA7L,0x843D3B56L,
+ 0xB2DBCC09L,0xB737BAF8L,0xB90321EBL,0xBCEF571AL,
+ 0xA56A17CDL,0xA086613CL,0xAEB2FA2FL,0xAB5E8CDEL,
+ 0xFDE39562L,0xF80FE393L,0xF63B7880L,0xF3D70E71L,
+ 0xEA524EA6L,0xEFBE3857L,0xE18AA344L,0xE466D5B5L,
+ 0xD28022EAL,0xD76C541BL,0xD958CF08L,0xDCB4B9F9L,
+ 0xC531F92EL,0xC0DD8FDFL,0xCEE914CCL,0xCB05623DL,
+ 0xA324FA72L,0xA6C88C83L,0xA8FC1790L,0xAD106161L,
+ 0xB49521B6L,0xB1795747L,0xBF4DCC54L,0xBAA1BAA5L,
+ 0x8C474DFAL,0x89AB3B0BL,0x879FA018L,0x8273D6E9L,
+ 0x9BF6963EL,0x9E1AE0CFL,0x902E7BDCL,0x95C20D2DL,
+ 0x406D4B42L,0x45813DB3L,0x4BB5A6A0L,0x4E59D051L,
+ 0x57DC9086L,0x5230E677L,0x5C047D64L,0x59E80B95L,
+ 0x6F0EFCCAL,0x6AE28A3BL,0x64D61128L,0x613A67D9L,
+ 0x78BF270EL,0x7D5351FFL,0x7367CAECL,0x768BBC1DL,
+ 0x1EAA2452L,0x1B4652A3L,0x1572C9B0L,0x109EBF41L,
+ 0x091BFF96L,0x0CF78967L,0x02C31274L,0x072F6485L,
+ 0x31C993DAL,0x3425E52BL,0x3A117E38L,0x3FFD08C9L,
+ 0x2678481EL,0x23943EEFL,0x2DA0A5FCL,0x284CD30DL,
+ 0x83125FD3L,0x86FE2922L,0x88CAB231L,0x8D26C4C0L,
+ 0x94A38417L,0x914FF2E6L,0x9F7B69F5L,0x9A971F04L,
+ 0xAC71E85BL,0xA99D9EAAL,0xA7A905B9L,0xA2457348L,
+ 0xBBC0339FL,0xBE2C456EL,0xB018DE7DL,0xB5F4A88CL,
+ 0xDDD530C3L,0xD8394632L,0xD60DDD21L,0xD3E1ABD0L,
+ 0xCA64EB07L,0xCF889DF6L,0xC1BC06E5L,0xC4507014L,
+ 0xF2B6874BL,0xF75AF1BAL,0xF96E6AA9L,0xFC821C58L,
+ 0xE5075C8FL,0xE0EB2A7EL,0xEEDFB16DL,0xEB33C79CL,
+ 0x3E9C81F3L,0x3B70F702L,0x35446C11L,0x30A81AE0L,
+ 0x292D5A37L,0x2CC12CC6L,0x22F5B7D5L,0x2719C124L,
+ 0x11FF367BL,0x1413408AL,0x1A27DB99L,0x1FCBAD68L,
+ 0x064EEDBFL,0x03A29B4EL,0x0D96005DL,0x087A76ACL,
+ 0x605BEEE3L,0x65B79812L,0x6B830301L,0x6E6F75F0L,
+ 0x77EA3527L,0x720643D6L,0x7C32D8C5L,0x79DEAE34L,
+ 0x4F38596BL,0x4AD42F9AL,0x44E0B489L,0x410CC278L,
+ 0x588982AFL,0x5D65F45EL,0x53516F4DL,0x56BD19BCL
+};
+
+/*
+ * Calculate a 4-byte suffix to match desired CRC32C
+ *
+ * @current_crc: CRC32C checksum of all bytes before the suffix
+ * @desired_crc: the checksum that we want to get after adding the suffix
+ *
+ * Outputs: @suffix: pointer to where the suffix will be written (4-bytes)
+ */
+static void find_collision_calc_suffix(unsigned long current_crc,
+ unsigned long desired_crc,
+ char *suffix)
+{
+ int i;
+
+ for(i = 3; i >= 0; i--) {
+ desired_crc = (desired_crc << 8)
+ ^ crc32c_rev_table[desired_crc >> 24 & 0xFF]
+ ^ ((current_crc >> i * 8) & 0xFF);
+ }
+ for (i = 0; i < 4; i++)
+ suffix[i] = (desired_crc >> i * 8) & 0xFF;
+}
+
+/*
+ * Check if suffix is valid according to our file name conventions
+ */
+static int find_collision_is_suffix_valid(const char *suffix)
+{
+ int i;
+ char c;
+
+ for (i = 0; i < 4; i++) {
+ c = suffix[i];
+ if (c < ' ' || c > 126 || c == '/')
+ return 0;
+ }
+ return 1;
+}
+
+static int find_collision_reverse_crc32c(struct name *val, u32 name_len)
+{
+ unsigned long checksum;
+ unsigned long current_checksum;
+ int found = 0;
+ int i;
+
+ /* There are no same length collisions of 4 or less bytes */
+ if (name_len <= 4)
+ return 0;
+ checksum = crc32c(~1, val->val, name_len);
+ name_len -= 4;
+ memset(val->sub, ' ', name_len);
+ i = 0;
+ while (1) {
+ current_checksum = crc32c(~1, val->sub, name_len);
+ find_collision_calc_suffix(current_checksum,
+ checksum,
+ val->sub + name_len);
+ if (find_collision_is_suffix_valid(val->sub + name_len) &&
+ memcmp(val->sub, val->val, val->len)) {
+ found = 1;
+ break;
+ }
+
+ if (val->sub[i] == 126) {
+ do {
+ i++;
+ if (i >= name_len)
+ break;
+ } while (val->sub[i] == 126);
+
+ if (i >= name_len)
+ break;
+ val->sub[i]++;
+ if (val->sub[i] == '/')
+ val->sub[i]++;
+ memset(val->sub, ' ', i);
+ i = 0;
+ continue;
+ } else {
+ val->sub[i]++;
+ if (val->sub[i] == '/')
+ val->sub[i]++;
+ }
+ }
+ return found;
+}
+
+static void tree_insert(struct rb_root *root, struct rb_node *ins,
+ int (*cmp)(struct rb_node *a, struct rb_node *b,
+ int fuzz))
+{
+ struct rb_node ** p = &root->rb_node;
+ struct rb_node * parent = NULL;
+ int dir;
+
+ while(*p) {
+ parent = *p;
+
+ dir = cmp(*p, ins, 1);
+ if (dir < 0)
+ p = &(*p)->rb_left;
+ else if (dir > 0)
+ p = &(*p)->rb_right;
+ else
+ BUG();
+ }
+
+ rb_link_node(ins, parent, p);
+ rb_insert_color(ins, root);
+}
+
+static struct rb_node *tree_search(struct rb_root *root,
+ struct rb_node *search,
+ int (*cmp)(struct rb_node *a,
+ struct rb_node *b, int fuzz),
+ int fuzz)
+{
+ struct rb_node *n = root->rb_node;
+ int dir;
+
+ while (n) {
+ dir = cmp(n, search, fuzz);
+ if (dir < 0)
+ n = n->rb_left;
+ else if (dir > 0)
+ n = n->rb_right;
+ else
+ return n;
+ }
+
+ return NULL;
+}
+
+static int name_cmp(struct rb_node *a, struct rb_node *b, int fuzz)
+{
+ struct name *entry = rb_entry(a, struct name, n);
+ struct name *ins = rb_entry(b, struct name, n);
+ u32 len;
+
+ len = min(ins->len, entry->len);
+ return memcmp(ins->val, entry->val, len);
+}
+
+static char *find_collision(struct rb_root *name_tree, char *name,
+ u32 name_len)
+{
+ struct name *val;
+ struct rb_node *entry;
+ struct name tmp;
+ int found;
+ int i;
+
+ tmp.val = name;
+ tmp.len = name_len;
+ entry = tree_search(name_tree, &tmp.n, name_cmp, 0);
+ if (entry) {
+ val = rb_entry(entry, struct name, n);
+ free(name);
+ return val->sub;
+ }
+
+ val = malloc(sizeof(struct name));
+ if (!val) {
+ error("cannot sanitize name, not enough memory");
+ free(name);
+ return NULL;
+ }
+
+ memset(val, 0, sizeof(*val));
+
+ val->val = name;
+ val->len = name_len;
+ val->sub = malloc(name_len);
+ if (!val->sub) {
+ error("cannot sanitize name, not enough memory");
+ free(val);
+ free(name);
+ return NULL;
+ }
+
+ found = find_collision_reverse_crc32c(val, name_len);
+
+ if (!found) {
+ warning(
+"cannot find a hash collision for '%.*s', generating garbage, it won't match indexes",
+ val->len, val->val);
+ for (i = 0; i < name_len; i++) {
+ char c = rand_range(94) + 33;
+
+ if (c == '/')
+ c++;
+ val->sub[i] = c;
+ }
+ }
+
+ tree_insert(name_tree, &val->n, name_cmp);
+ return val->sub;
+}
+
+static char *generate_garbage(u32 name_len)
+{
+ char *buf = malloc(name_len);
+ int i;
+
+ if (!buf)
+ return NULL;
+
+ for (i = 0; i < name_len; i++) {
+ char c = rand_range(94) + 33;
+
+ if (c == '/')
+ c++;
+ buf[i] = c;
+ }
+
+ return buf;
+}
+
+static void sanitize_dir_item(enum sanitize_mode sanitize,
+ struct rb_root *name_tree, struct extent_buffer *eb, int slot)
+{
+ struct btrfs_dir_item *dir_item;
+ char *buf;
+ char *garbage;
+ unsigned long name_ptr;
+ u32 total_len;
+ u32 cur = 0;
+ u32 this_len;
+ u32 name_len;
+ int free_garbage = (sanitize == SANITIZE_NAMES);
+
+ dir_item = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
+ total_len = btrfs_item_size_nr(eb, slot);
+ while (cur < total_len) {
+ this_len = sizeof(*dir_item) +
+ btrfs_dir_name_len(eb, dir_item) +
+ btrfs_dir_data_len(eb, dir_item);
+ name_ptr = (unsigned long)(dir_item + 1);
+ name_len = btrfs_dir_name_len(eb, dir_item);
+
+ if (sanitize == SANITIZE_COLLISIONS) {
+ buf = malloc(name_len);
+ if (!buf) {
+ error("cannot sanitize name, not enough memory");
+ return;
+ }
+ read_extent_buffer(eb, buf, name_ptr, name_len);
+ garbage = find_collision(name_tree, buf, name_len);
+ } else {
+ garbage = generate_garbage(name_len);
+ }
+ if (!garbage) {
+ error("cannot sanitize name, not enough memory");
+ return;
+ }
+ write_extent_buffer(eb, garbage, name_ptr, name_len);
+ cur += this_len;
+ dir_item = (struct btrfs_dir_item *)((char *)dir_item +
+ this_len);
+ if (free_garbage)
+ free(garbage);
+ }
+}
+
+static void sanitize_inode_ref(enum sanitize_mode sanitize,
+ struct rb_root *name_tree, struct extent_buffer *eb, int slot,
+ int ext)
+{
+ struct btrfs_inode_extref *extref;
+ struct btrfs_inode_ref *ref;
+ char *garbage, *buf;
+ unsigned long ptr;
+ unsigned long name_ptr;
+ u32 item_size;
+ u32 cur_offset = 0;
+ int len;
+ int free_garbage = (sanitize == SANITIZE_NAMES);
+
+ item_size = btrfs_item_size_nr(eb, slot);
+ ptr = btrfs_item_ptr_offset(eb, slot);
+ while (cur_offset < item_size) {
+ if (ext) {
+ extref = (struct btrfs_inode_extref *)(ptr +
+ cur_offset);
+ name_ptr = (unsigned long)(&extref->name);
+ len = btrfs_inode_extref_name_len(eb, extref);
+ cur_offset += sizeof(*extref);
+ } else {
+ ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
+ len = btrfs_inode_ref_name_len(eb, ref);
+ name_ptr = (unsigned long)(ref + 1);
+ cur_offset += sizeof(*ref);
+ }
+ cur_offset += len;
+
+ if (sanitize == SANITIZE_COLLISIONS) {
+ buf = malloc(len);
+ if (!buf) {
+ error("cannot sanitize name, not enough memory");
+ return;
+ }
+ read_extent_buffer(eb, buf, name_ptr, len);
+ garbage = find_collision(name_tree, buf, len);
+ } else {
+ garbage = generate_garbage(len);
+ }
+
+ if (!garbage) {
+ error("cannot sanitize name, not enough memory");
+ return;
+ }
+ write_extent_buffer(eb, garbage, name_ptr, len);
+ if (free_garbage)
+ free(garbage);
+ }
+}
+
+static void sanitize_xattr(struct extent_buffer *eb, int slot)
+{
+ struct btrfs_dir_item *dir_item;
+ unsigned long data_ptr;
+ u32 data_len;
+
+ dir_item = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
+ data_len = btrfs_dir_data_len(eb, dir_item);
+
+ data_ptr = (unsigned long)((char *)(dir_item + 1) +
+ btrfs_dir_name_len(eb, dir_item));
+ memset_extent_buffer(eb, 0, data_ptr, data_len);
+}
+
+static struct extent_buffer *alloc_dummy_eb(u64 bytenr, u32 size)
+{
+ struct extent_buffer *eb;
+
+ eb = calloc(1, sizeof(struct extent_buffer) + size);
+ if (!eb)
+ return NULL;
+
+ eb->start = bytenr;
+ eb->len = size;
+ return eb;
+}
+
+void sanitize_name(enum sanitize_mode sanitize, struct rb_root *name_tree,
+ u8 *dst, struct extent_buffer *src, struct btrfs_key *key,
+ int slot)
+{
+ struct extent_buffer *eb;
+
+ eb = alloc_dummy_eb(src->start, src->len);
+ if (!eb) {
+ error("cannot sanitize name, not enough memory");
+ return;
+ }
+
+ memcpy(eb->data, src->data, src->len);
+
+ switch (key->type) {
+ case BTRFS_DIR_ITEM_KEY:
+ case BTRFS_DIR_INDEX_KEY:
+ sanitize_dir_item(sanitize, name_tree, eb, slot);
+ break;
+ case BTRFS_INODE_REF_KEY:
+ sanitize_inode_ref(sanitize, name_tree, eb, slot, 0);
+ break;
+ case BTRFS_INODE_EXTREF_KEY:
+ sanitize_inode_ref(sanitize, name_tree, eb, slot, 1);
+ break;
+ case BTRFS_XATTR_ITEM_KEY:
+ sanitize_xattr(eb, slot);
+ break;
+ default:
+ break;
+ }
+
+ memcpy(dst, eb->data, eb->len);
+ free(eb);
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-20 00:18:26 +0000